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Objective
Maternal vitamin D deficiency is a prevalent public health issue worldwide. While isolated reports from certain cities in China have highlighted the existence of maternal vitamin D deficiency, no nationwide investigation has been conducted on this topic. Therefore, we conducted a meta-analysis and systematic review to examine the prevalence and associated influencing factors of maternal vitamin D deficiency in mainland China. This study aims to provide a theoretical foundation for future prevention and supplementation strategies for maternal vitamin D.
Methods
We retrieved relevant Chinese and English literature on the status of maternal vitamin D deficiency in mainland China from databases such as CNKI, Wanfang Data, VIP, CBM, Web of Science, Google Scholar, and PubMed. The literature search and database construction were conducted until September 8, 2023. Data were extracted and synthesized following PRISMA guidelines.After literature screening and quality assessment, we performed meta-analysis, sensitivity analysis, and identified publication bias using RevMan 5.3 software.
Results
A total of 26 articles were reviewed, involving 128,820 pregnant women. Among them, 108,768 had vitamin D insufficiency or deficiency, resulting in a prevalence of 84% (95% CI: 81%~88%). Subgroup analysis revealed the highest prevalence of vitamin D deficiency or insufficiency among pregnant women in mainland China to be in the northwest region (94%, 95% CI: 94%~95%). Furthermore, the highest prevalence was observed during the winter and spring seasons (80%, 95% CI: 77%~83%) and in the early stages of pregnancy (93%, 95% CI: 90%~95%). Significant statistical differences (P<0.05) were found among these three subgroups. No publication bias was detected, and sensitivity analysis indicated the stability of the meta-analysis outcome.
Conclusion
This study provides evidence of the prevalence of vitamin D deficiency or insufficiency among pregnant women in mainland China. To improve the overall health and well-being of the population, relevant health authorities should develop policies aimed at alleviating this phenomenon.

目的
孕产妇维生素D缺乏是全球范围内普遍存在的公共卫生问题。尽管我国部分城市已有零星报道提及孕产妇维生素D缺乏的存在，但目前尚未开展针对该主题的全国性调查。为此，本研究通过荟萃分析与系统评价，探讨我国大陆地区孕产妇维生素D缺乏的流行现状及相关影响因素，旨在为未来孕产妇维生素D的预防与补充策略提供理论依据。

方法
本研究从中国知网（CNKI）、万方数据（Wanfang Data）、维普资讯（VIP）、中国生物医学文献数据库（CBM）、Web of Science、Google Scholar及PubMed等数据库中，检索有关我国大陆地区孕产妇维生素D缺乏现状的中英文相关文献。文献检索与数据库构建工作截至2023年9月8日完成。研究数据的提取与合成严格遵照PRISMA指南。在完成文献筛选与质量评价后，采用RevMan 5.3软件开展荟萃分析、敏感性分析，并识别发表偏倚。

结果
本研究最终纳入26篇文献，共涉及128820名孕产妇，其中108768名存在维生素D不足或缺乏，整体流行率为84%（95%置信区间：81%~88%）。亚组分析显示，我国大陆地区孕产妇维生素D不足或缺乏的流行率以西北地区最高，达94%（95%置信区间：94%~95%）。此外，冬春季节（80%，95%置信区间：77%~83%）及妊娠早期（93%，95%置信区间：90%~95%）的流行率亦处于较高水平。上述三个亚组间的差异具有统计学意义（P<0.05）。本研究未检测到发表偏倚，敏感性分析证实本次荟萃分析结果具有稳定性。

结论
本研究证实了我国大陆地区孕产妇维生素D不足或缺乏的流行现状。为提升全民整体健康水平与生活质量，相关卫生主管部门应制定针对性政策以改善这一现象。